Bob,
I am a member of the PRR T&HS and the B&O HS. I let both of those groups know of road specific projects coming from Sunset / 3rd Rail and Golden Gate.
I do know members of a number of other railroads' historical societies and confer with them on Sunset/GGD projects and ask them to pass new project information to their respective groups.
This week I will be at York and next week at the PRR T&HS convention near Harrisburg with the Sunset/GGD display.
I can't speak for what other importers' stance is on this topic.